Earth drilling device



Dec. 20, 1949 J. E. ROBERTS E1 AL. 2,491,908

EARTH DRILLING DEVICE Filed Aug. 11, 1945 3 Sheets-Sheet 1 3E INVEN TORS J9me: ,5 Eaeaem Dec. 20, 1949 J. E. ROBERTS ET AL 2,491,908

EARTH DRILLING DEVICE Filed Aug. 11, 1945 :s Sheets-Sheet 2 M JNVENTORS TAME'S E. Qoaam-s 32 12 ALBERT O. 'Qoaam-s Dec. 20, 1949 J. E. ROBERTS ET AL EARTHDRILLING DEVICE Filed Aug. 11, 1945 5 Sheets-Sheet 3 Ill Patented Dec. 20,, 1949 UN IT'ED 2,491,908 EARTH DEVICE J amesiEsRoherts;Driontllls andAlbert 0." Roberts, Dearborm, Mich.

ApplicationA'ugust 1'1, 1945;"SeriaPNo'. 6103242 8 Claims: 1-1

The present inventi'onrelates-to an earthdrill, ing'device, particularly'adapted -fondrilling oylindrical holes 0f variousxlepths in -theiearth,'- and -is particularly but not exclusively adapted for' the drilling of such holes to useas holes for s fence posts; utilitypoles; footings, wells, and the like;

A primary-object of the present invention isto provide an earth drilling device: which may be mountedon a truck or similar vehicle and which iswso constructed. as to "be; readily r portable and adapted for use in restricted areas, the unitbeing compact its desigrnahd speedyand eificient in itsdrilling action.-

A further: object of thepresent inventionis to provide an earth drilling device which m-ay: be operated while suspendedwith 'its drill endportion. in contact with: the surface to be drilled} and which by reason of its design -isfree of re action torque; thus providing compact and efficient tool which; does not require structural supporting members =or the like to resist its counter rotation.

Alfurther" object lof the present invention is =-to provide an earth: drilling device particularly adapted for drillingcylindrical holes of relatively shallow depth in top soils; thedevice being-par-- ticularly adapted for the drilling of holes forthe-setting of fence posts or the like;

Other objects of this invention will appearin the following description and appended claims, reference .beinghad' to the accompanyihg dra-wings forming a part of this specification wherein like reference characters designate-"corresponding parts in the several views.

Inxthe drawings Fig. 1 is aufragmentary side elevation of the rearendsof a motor truck or: other wheeled"ve-- hicle showing an earth drilling device of-the pres-#- ent invention after removal fromiaicylindrical hole drilled by it.

Fig. 2- is a cross-sectional view of the device:

shown in Fig. 1. taken substantially.on-the line.

2-2 in the direction. of the arrows, Fig.1.

Fig. 3 is an endview of. the earth drillingdevice.

of the present invention taken substantially along the line 3-3 in the direction of thearrows, Fig. .1.

Fig. 4 is a fragmentary side elevationof the device of the present" invention showing the. meshed arrangement" of the; separate; earth angers.

Fig; 5:. 18. a fragmentary: sectional. viewe of a portion ofthedrive headiof. theearthdrillihgdea ViCBQOf the present inventiomtaken substantially.- onzthe: staggeredlsection line; 5..-5. inthe direction of. the arrows; Fig. 2&

Fig; dis a fragmentary viewtof a portion of; the drives. head of the 1' device.:.

Before explaining in detail thespresent. inven. tion, ittis. to. be understood. that. thetinvention. is not: limited in itsv applicationto.. the. detailsv of: construction andzarrangement;of parts.1.i11ustrated. in. the; accompanying; drawings, since; the inven.-.- tionis capable of. other; embodimentsandof. be.- ing practiced or. carried out in .various ways. Also it. is. to; be. understood; that. the phraseology or terminology employedi herein for. the purpose of.description and not. ofilimitation.

The earth. drilling device. oflthe present driventionr comprises alhousing. 9.3into.:which extends the power :output shaft l ii :of anelectrimmotor I l. whichismountedon .the housing 9: The-power outputshaft l0 istkeyed to a;drive. shaftr.l2ljourrnaled;in.an.end.;bearingl3. A; piniongear 55153 keyed... at i 4 to. the'.'sha-ft:. l 2 K and :is. meshech with a cluster l6 ofplanetary gears. carried. in the. planetary gearcarrier I "I; whichzislcarriedomthe shaft: I 2 and iszfrees to; travel around. the shaft; I2t Aisun gear. I8, integralywith the planetary" gear carrier: li ismeshed'with'arsecond planetary. gear. cluster l9; whichisrmountedaon the plane+- tary gearcarrier. 2ll.secur.ed.to the:hub. of a. gear- 2]. meshed with. aplurality of. gears;22;.one; of; which. is keyed to.-each1ofrone:t Off a plurality of.-

symmetrically disposed: circumferentially spacedshafts 231by'a-key. 2.4. The shaftsc23 316193.011 journaled at. their: ends :in. bearings- 25. andv 26. A; plurality.- of. symmetrically; disposed circum ferentially spaced earthlaugerslzil, iiLthe present instance. four in number; are.provided',. one being connected for: rotation. with each of the; shafts 23. Thetwo sets of .planetarylgear clusters" I5 and l 9 (are. meshed with an internally toothed ring gear 28 secured. totherhousingal.

The-housing fi-provideslthe casingfor thez geari trains which transmit the driving torquegfrom.

the power output shaft lihofthesmotor. H to:the separate. earth angers... Thehousing. 9ris. filled,- with asuitablegear lubricant through the plugflt.

Referring. to.Fig..2 it will be seen that in; the present instance four of the shafts 23 are pros vided. Each is provided with the gearing and bearings previously described. Interposed between adjacent spaced shafts 23 are a like number of shafts 29, each of which is journaled at its ends for rotation about its longitudinal axis. The shafts 29 are driven from the shafts 23 in an opposite direction of rotation by the meshed spur gears 30 and 30a mounted respectively on the shafts 23 and the adjacent shafts 29.

An earth auger 40 is secured to each of the shafts 2% The earth augers it are provided with double threaded spiral flutes 41 adjacent the end portions thereof, which are meshed with the adjacent double thread spiral flutes 3i on the ends of the earth augers 21. The flutes 3i and M are reversably directed as shown in Fig. 3 by the direction arrows, one auger 21 and one auger 40 forming a working pair rotating in opposite directions.

As shown in Fig. 3, the double thread spiral flutes iii of the augers 21 mesh with the double thread spiral flutes ii of the augers 4t and completely enclose a circle whose diameter is approximately the diameter of the hole to be drilled. Each of the double thread spiral threads 3i and 41 are provided with a plurality of earth cutting edges 32 which provide a positive cutting and breaking of the earth with which the earth augers are brought into contact. The loosened earth is fed upwardly from the double thread spiral flutes 3i and 4| to the spiral conveying flutes 42, which are provided on each of the augers 2? and 40.

As will be seen, the gearing previously described provides for power driving each auger 27 and do. The earth drilling device as a whole does not rotate. The drilling action results from the rotation of the augers in each pair of augers which separately rotate about their own axes in opposite directions of rotation. In this manner, a plurality of relatively small holes, in the present instance eight in number, are provided and the edges of each of the said holes join with the edges of the next adjacent small hole so that a central core is completely freed from the surrounding earth surface. In certain types of soils the central core will be broken by the drilling action of the augers, but in other types of soilsv the central core may be continually elevated by the operation of the spiral conveyors 42. To break up the central core in such instance, an earth breaking point 43 is secured to the central portion of the bottom of the housing 9, and extends any desired distance downwardly into the center of the space surrounded by the said augers. When an unbroken core is raised by the conveyor flutes 42, it is fed against the sharp end of the earth breaking point 43 and is thereby broken into smaller portions which are readily conveyed with the other loosened parts of the earth freed from the hole and is discharged in the piles 38 surrounding the circumferential edge portions of the drilled hole.

The earth drilling device of the present invention is preferably used as indicated in Fig. l where it is mounted on a motor truck or similar wheeled conveyance having a crane arm 33 which is raised or lowered by the operation of a hand or power operated winch 34 by means of the cable 35 The earth drilling device of the present invention is suspended from the end of the crane arm 33 by a cable 36 which is connected with a winch 31 for raising and lowering the device relative to the surface to be drilled. Electric power to operate the motor II is transmitted from a suitable source of power which may be either a power generator mounted upon the truck, or the power may be secured from a power line, if available. In either instance, the power is transmitted through a power cable which is preferably co-axial with the cable 36 and hence is not shown in the drawing.

In operation, the earth drilling device of the present invention is lowered into contact with the surface to be drilled and power is then applied to the operating motor H, which is transmitted through the gearing previously described to effect the separate rotation of the augers 21 and it in opposite directions. The flutes on the adjacent augers 2'5 and 4B are pitched in oppositedirections so that the rotation of the augers in opposite directions causes the loosened material to be fed upwardly and out of the drilled hole.- The cutting edges 32 of the double spiral fluted portions 3| and 4| of the augers penetrate the surface of the earth and feed the loosened earth to the conveyor flutes 42. The conveyor flutes 42 extend upwardly in a spiral about each of the earth augers and deliver the loosened earth at the discharge point adjacent the circumference of the drilled hole in mounds spaced radially thereof. The drilling is continued until the desired depth of hole is reached, after which the winch 31 is operated and the entire drilling device is elevated from the hole. The crane arm 33 may then be raised and the entire device readily transported to a new location.

From the foregoing it will be seen that we have provided a novel and simplified construction of an earth drilling device which is particularly adapted to the drilling of relatively shallow holes of relatively small diameter, such as are used for the placement of fence posts or the like. It is to be understood, however, that the device of the present invention is not particularly limited to such use, but may be used to provide cylindrical holes in the earths surface for any desired purpose. While eight augers are here shown symmetrically spaced circumferentially about a central point, it is to be understood that the invention is not limited to this particular number of augers, for in certain instances and in certain types of soil a larger number of relatively smaller augers may be desirable, while in other instances a relatively smaller number of larger augers may be provided.

We claim:

1. An earth drilling device including a housing, a non-rotatable earth breaking point extending downwardly therefrom, a plurality of separate rotatable earth augers depending from said housing and symmetrically disposed about a circle, the center of which lies on the longitudinal axis of said earth breaking point, each of said augers havin spiral flutes terminating in an earth cutting surface, and having a diameter less than the diameter of the finished hole and power means connected with said augers for simultaneously rotating said augers to drill a plurality of circumferentially spaced intercommunicating cylindrical holes at the outer periphery of the hole to be drilled and to free a central core portion thereof.

2. An earth drilling device including a nonrotatable. housing, a plurality of symmetrically disposed circumferentially spaced separate roamen ties mumeaung cylindrical holes surrounding a centra'l core portion, and a non-rotatable earth breaking point fixed to said housing and :depending downwardly therefrom centrally or said separate earth augers for breaking the earth in said central core portion as it is elevated from the hole by said spiral flutes.

3. An earth drilling device including a nonrotatable housing, a plurality of symmetrically disposed circumferentially spaced separate earth augers depending from said housing and having spiral flutes overlappin spiral flutes of an adjacent auger, said flutes each terminating in an earth cutting surface, power means connected with said augers for simultaneously rotating each of said augers in a direction opposite to the direction of rotation of the adjacent augers to drill a plurality of circumferentially spaced intercommunicating cylindrical holes surrounding a central core portion, a spiral conveyor flute on each of said augers for elevating from the drilled holes the earth loosened by the earth cutting surfaces of said intermeshed spiral flutes and for discharging said loosened earth outside of the drilled hole, and a fixed earth breaking point secured to said housing and depending downwardly therefrom adjacent the top portions of said conveyor flutes and centrally of said separate augers for breaking up earth when raised by said augers from said central core portion.

4. An earth drilling device including a nonrotatable housing, a plurality of separate rotatable earth augers depending from said housing and symmetrically disposed circumferentially thereof, said augers having spiral flutes each terminating in an earth cutting surface, power means connected with said augers and including an electric motor mounted on said housing, connected with a power source and having a power output shaft extending into said housing and geared with said separate earth augers for simultaneously rotating said augers in pairs, the augers in each pair being rotated in opposite directions thereby to drill and clear a plurality of circumferentially spaced intercommunicating cylindrical holes surrounding a central core por-- tion, and a conical earth-breaking point having its base secured to said housing centrally of said augers and having its apex extending downwardly therefrom adjacent the top portions of said flutes and adapted to break up the earth in said central core portion when raised from the hole by the action of said flutes.

5. An earth drilling device including a nonrotatable housing, a plurality of separate earth augers depending from said housing and symmetrically disposed circumferentially thereof, each of said augers having an earth cutting surface formed on the end thereof, an electric motor mounted on said housing, connected with a power source, and having a power output shaft extending into said housing and geared with said separate earth augers for simultaneously rotating all of said augers to drill a plurality of circumferentially spaced intercommunicating tion, and a spiral conveyor flute on :each of said :augersxfor elevating :from the drilled hole the 'earth loosened by the action of thecutting surfaces on said augers and for discharging said loosened *earth outside of the drilled hole, and an earth-breaking point extending downwardly fromsaid housing and centrally of said separate earth augers and extending to a point adjacent "the top'lportions of said flutes to break up "the earth in said core when-elevated from the drilled hole by the action of said flutes.

fin-An earth drilling-device including a nonrotatable housing, means for suspending said housing from *a'flexible cable, a plurality of separate earth augers depending from said housing and symmetrically disposed circumferentially thereof and having intermeshed spiral flutes each terminating in an earth cutting surface, and an electric motor mounted on said housing and connected with a power source and having a power output shaft extending into said housing and geared with said separate earth augers for simultaneously rotating said augers in pairs, the augers of each pair rotating in opposite directions to drill a plurality of circumferentially spaced interconnected cylindrical holes surrounding a central core portion, a spiral conveyor flute on each of said augers for elevating from the drilled hole the earth loosened by said intermeshed spiral flutes and for discharging said loosened earth outside of the drilled hole, and an earth breaking point secured to said housing and depending downwardly therefrom centrally of said separate augers for contact with the earth in said central core portion.

7. An earth drillin device including a housing, an earth-breaking point extending downwardly therefrom, a plurality of separate earth augers depending from said housing and symmetrically disposed about a circle, the center of which lies on the longitudinal axis of said earthbreaking point, each of said augers having intermeshed spiral flutes each terminating in an earth cutting surface, an electric motor mounted on said housing and connected with a power source and having a power output shaft extending into said housing, a planetary gear train connected with said power output shaft and with said earth augers for rotating certain of said earth augers in one direction and a gear train connecting said certain of said earth augers with the other of said earth augers for separately rotating said augers in pairs in opposite directions, thereby to drill a plurality of circumferentially spaced intercommunicating cylindrical holes surrounding a central core portion.

8. An earth drilling device including a housing, a plurality of separate earth augers depending from said housing and symmetrically disposed circumferentially thereof and having intermeshed spiral flutes each terminating in an earth cuttin surface, an electric motor mounted on said housing and connected with a power source and having a power output shaft extending into said housing, a planetary gear train connected with said power output shaft and with said earth augers for rotating certain of said earth augers and a gear train connecting said certain of said earth augers with the other of said earth augers for separately rotating said augers in pairs in opposite directions, thereby to drill a plurality of circumferentially spaced intercommunicating cylindrical holes surrounding a central core portion, a spiral conveyor flute on each of said augers for elevating from the drilled hole the earth loosened by the earth cutting surfaces of said intermeshed spiral flutes 5 and for discharging said loosened earth outside of the drilled hole, and an earth breaking point secured to said housing and depending downwardly therefrom centrally of said augers for contact with earth raised from the central core portion of said drilled hole.

JAMES E. ROBERTS.

ALBERT 0. ROBERTS.

REFERENCES CITED The following references are of record in the file of this patent:

Number 8 UNITED STATES PATENTS Name Date f Raymond Aug. 24, 1897 Farquhar May 7, 1907 Wadsworth Apr. 12, 1921 Gilthorpe Sept. 20, 1921 McFadden June 6, 1922 Bullock Jan. 20, 1925 Jones Dec. 25, 1928 Swift et al. Aug. 27, 1929 Bogoutsky Jan. 15, 1935 Miller Aug. 1'7, 1937 Certificate of Correction Patent No. 2,491,908 December 20, 1949 JAMES E. ROBERTS ET AL. It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, lines 63 and 64, and column 6, lines 13 and 14, strike out the word 1 non-rotatable;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent ()ffice.

Signed and sealed this 30th day of May, A. D. 1950.

THOMAS F. MURPHY,

Assistant G'ommissioner of Patents. 

